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Experimental Investigation and Thermodynamic Modeling of the ZrO 2 –SmO 1.5 System
Author(s) -
Wang Chong,
Zinkevich Matsvei,
Aldinger Fritz
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01692.x
Subject(s) - fluorite , pyrochlore , calphad , phase (matter) , phase diagram , tetragonal crystal system , calorimetry , materials science , analytical chemistry (journal) , crystallography , atmospheric temperature range , thermodynamics , chemistry , mineralogy , metallurgy , physics , organic chemistry , chromatography
Phase equilibria of the ZrO 2 –SmO 1.5 system have been studied by X‐ray diffraction, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The compositions of phases in the tetragonal+fluorite, fluorite+pyrochlore, and fluorite+B‐Sm 2 O 3 two‐phase fields have been determined for samples quenched from temperatures between 1400° and 1700°C. The heat content of the fluorite phase with 30 mol% SmO 1.5 and of the pyrochlore phase with 50 mol% SmO 1.5 has been measured in the temperature range 200°–1400°C using high‐temperature drop calorimetry. The transition between pyrochlore and fluorite phases is clearly first order in the SmO 1.5 ‐rich region, while no fluorite+pyrochlore two‐phase region has been detected for the samples with ZrO 2 excess. Based on the obtained experimental results and literature data, the phase diagram and thermodynamic properties were optimized using the CALPHAD approach.